High voltage linear tap changer

Abstract

A high voltage electrical switching apparatus including a base formed from a pair of flat dielectric plates supported in a spaced relation, a number of elongate elliptically shaped contacts positioned between the plates at equally spaced intervals, a dielectric bar mounted for linear motion between the plates, a pair of electrically conductive plates mounted on opposite sides of the bar, each conductive plate including a pair of louvered contacts spaced a distance apart sufficient to electrically interconnect two of the elongate contacts, and a Geneva drive assembly for moving the bar in steps of equal distance.

I claim: 
     
       1. A high voltage tap changer comprising a pair of flat plates,   a number of fixed current carrying contacts mounted between said plates in an equally spaced relation,   said current carrying contacts having flat surfaces on each side,   a bar supported for reciprocal motion between said plates,   a pair of sliding current carrying contacts mounted on said bar, said sliding current carrying contacts being spaced apart a distance greater than the thickness of said fixed contacts and being of a length to interconnect two fixed contacts at any one time,   a louvered contact means mounted on said current carrying contacts in an opposing relation and being spaced apart a distance less than the thickness of said fixed contacts, and   means for moving said bar in a step-by-step manner, said moving means including a Geneva drive mechanism for moving said bar one step in each revolution of the drive mechanism.   
     
     
       2. The tap changer according to claim 1 wherein said moving means includes a number of slots spaced equal distances apart on said bar and   said Geneva drive mechanism includes a wheel having a pin positioned to engage one slot in each revolution of the drive mechanisms.   
     
     
       3. The tap changer according to claim 1 wherein each of said fixed contacts comprises an elongate copper bar having a flat contact surface on each side of one end of the bar and   a number of openings at the other end,   a crimp connector positioned in each of said openings and being adapted to be connected to the conductive member of a high voltage cable.   
     
     
       4. The tap changer according to claim 1 wherein said current carrying contacts each comprise a flat plate, and said louvered contact means including a pair of louvered sections on one side of said current carrying contacts, said plates being positioned with said louvered sections in opposing relation to provide frictional contact between said louvered sections and the flat contact surface on said fixed contacts on movement into engagement with said fixed contacts. 
     
     
       5. A high voltage tap changer comprising a pair of plates formed from dielectric material,   means for supporting said plates in a parallel spaced relation,   a number of flat electrical contacts supported in a spaced relation between said plates,   a bar formed from a dielectric material and means for supporting said bar for reciprocal motion between said plates,   an electrically conductive plate mounted on each side of said bar in opposing relation, said conductive plates being spaced apart a distance greater than the thickness of said contacts, a pair of louvered contacts mounted on each conductive plate in an opposed relation to a corresponding pair of louvered contacts mounted on the other conductive plate to provide an interference fit between the louvered contacts and said electrical contacts on moving said plates over said contacts, and   drive means for moving said bar in steps of equal length in both directions of motion.   
     
     
       6. The tap changer according to claim 5 wherein said drive means comprises a Geneva drive mechanism having a drive wheel mounted between said dielectric plates and having a signal drive pin located at the outer circumference of said drive wheel, and   a plurality of slots in said bar located a predetermined distance apart to allow for said pin to move into one slot in each direction of rotation of said drive wheel.   
     
     
       7. The tap changer according to claim 5 or 6 wherein each of said electrical contacts comprise an elongate copper bar having a flat contact surface on each side of one end of the bar, and a number of openings in the flat contact surface at the other end,   a crimp connector supported in each of said openings and being adapted to be connected to a high voltage cable.   
     
     
       8. A linear type tap changer for a power transformer comprising a number of flat electrically conductive members adapted to be connected to the transformer,   dielectric means for supporting said conductive members in a linear relation at equally spaced intervals,   linearly movable contact means mounted on said dielectric supporting means and including louvered contacts for movement into electrical engagement with said electrically conductive members,   and means for moving said contact means in a step by step manner through steps of equal distance whereby said contact means will positively engage two electrical contact members after each step of motion.   
     
     
       9. The tap changer according to claim 8 wherein said moving means includes a Geneva drive mechanism mounted on said support means and being operatively connected to said linearly movable contact means.   
     
     
       10. The tap changer according to claim 9 wherein said drive mechanism includes a Geneva drive wheel having a pin located on the wheel in a position to operatively engage said movable contact means in each revolution of the drive wheel.   
     
     
       11. The tap changer according to claim 8 including a tubular crimp connector mounted on a flat side of each of said electrically conductive members for connecting the tap changer to the transformer.